Commit 84e8dcf2 authored by Shigeru Yoshida's avatar Shigeru Yoshida Committed by Zizhi Wo
Browse files

fs/ntfs3: Avoid UBSAN error on true_sectors_per_clst() 

stable inclusion
from stable-v5.15.45
commit 4b51f27d4448c84957bce190292f75d4896d56b3
category: bugfix
bugzilla: https://gitee.com/src-openeuler/kernel/issues/IBP6TI
CVE: CVE-2022-49553

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=4b51f27d4448c84957bce190292f75d4896d56b3

--------------------------------

syzbot reported UBSAN error as below:

[   76.901829][ T6677] ================================================================================
[   76.903908][ T6677] UBSAN: shift-out-of-bounds in fs/ntfs3/super.c:675:13
[   76.905363][ T6677] shift exponent -247 is negative

This patch avoid this error.

Link: https://syzkaller.appspot.com/bug?id=b0299c09a14aababf0f1c862dd4ebc8ab9eb0179


Fixes: a3b77434 (fs/ntfs3: validate BOOT sectors_per_clusters)
Cc: Author: Randy Dunlap <rdunlap@infradead.org>
Reported-by: default avatar <syzbot+35b87c668935bb55e666@syzkaller.appspotmail.com>
Signed-off-by: default avatarShigeru Yoshida <syoshida@redhat.com>
Signed-off-by: default avatarKonstantin Komarov <almaz.alexandrovich@paragon-software.com>
Signed-off-by: default avatarZizhi Wo <wozizhi@huawei.com>
parent 2fb78222

fs/ntfs3/super.c

+1 −1
Original line number Diff line number Diff line
@@ -671,7 +671,7 @@ static u32 true_sectors_per_clst(const struct NTFS_BOOT *boot) 
	if (boot->sectors_per_clusters <= 0x80)

		return boot->sectors_per_clusters;

	if (boot->sectors_per_clusters >= 0xf4) /* limit shift to 2MB max */

		return 1U << (0 - boot->sectors_per_clusters);

		return 1U << -(s8)boot->sectors_per_clusters;

	return -EINVAL;

}